Conrad scheaube and carl schmidt



UNTTE STaTns PATENT Optics.

ASSIGNORS TO PLACE.

THE BADISCHE ANILlN AND SODA FABRIK, OF SAME NITROSAMIN COMPOUND.

SPECIFICATION forming part of Letters Patent No. 531,974, dated January 1, 1895. Application filed July 30, 1894. Serial No. 519,023. (Specimens) Patented in France November 13, 1893, No. 234,029.

To all 1072,0722, it may concern:

Be it known that we, CONRAD SCHRAUBE and CARL SCHMIDT, doctors of philosophy, subjects of the King of Prussia, German Emperor, residing at Ludwigshafen-on-the-Rhine, in the Kingdom of Bavaria and Empire of Germany, have invented new and usefullmprovements in the Manufacture of a New Nitrosamin Compound Derived from Benzidin, (for which a patent has been obtained in France November 13, 1898, No. 234,029, certificat daddition of February 5, 1894,) of which the following is a specification.

In the production of certain shades of color by means of one well-known process the dyer combines diam-compounds with amins or phenols on or in the presence of the fiber itself. Now since the diam-compounds generally are an extremely unstable class of bodies, it is necessary that they should be prepared in the dyeing factory as they cannot practically be transported. The preparation of the diazocompounds for the purpose in question is frequently an inconvenient or difficult matter as the best result can only be attained by careful and accurate observance of certain nan rowlybounded conditions. Moreovertheconditions which are best for obtaining the diazo-conopounds sometimes yield these bodies admixed with acids and salts in such quantity that the product is not well suited for use in the dyeing process mentioned.

lVe have discovered that on treating diazocompounds such as are hereinafter more particularly defined with caustic alkalies they are converted ultimately into the alkali-salts of the isomeric nitrosamins which compounds can easily beisolated and possess considerable stability. These constitute a new class of compounds and are characterized by the following generic properties: They are soluble in water, giving a somewhat alkaline solution and yield practically no dye in aqueous solution with a solution of naphthol in an excess of alkali. By treatment with the equivalent proportion of an acid these alkali-salts are in many cases converted into the free nitrosamin which is less stable than the alkali salt but can in some cases if desired be prepared in the solid state and used in the form of paste. On treatment with a larger proportion of acid preferably in the presence of a little nitrous acid, the bodies of this new class are smoothly and readily reconverted into the corresponding diazo-compounds. Thus 5 with beta-naphthol or other suitable compo nent and this mixture is printed on the fiber and the color developed by means of a weal: acid such as acetic acid or the carbonic acid of the atmosphere. In some cases this application constitutes the principal use of our new nitrosalnins.

The processes above described for the production of our new nitrosarnins can be ap plied to a large variety of diam-compounds.

The conversion into uitrosamin is most easily effected in the case of the diam-compounds which contain one or more acid substituting groups such as nitro-groups or two or more halogens and the like. Thus [oi-instance the diam-compounds from the nitro-anilius, di-

ohloro-anilin, and nitro-benzidin can be converted into the corresponding nitrosamins of the new class by treatment with caustic soda at the ordinary temperature. On the other hand the diam-compounds from anilin, toluidin,

naphthylamin, benzidin and the like which contain no acid substituting groups must be heated with strong alkalies at the temperature of the water-bath or higher in order to effect the desired conversion. two extreme groups of diam-compounds there are ranked sulfoacids and all such diazo-con1 pounds as contain on the whole less strongly acid substituting groups than those first mentioned, such for instance as the diazo-com- 5 pounds from sulfanilic acid, para-brom-anilin and the like, and these can be converted into the nitrosamins of the new class by treat- Further in addition to these ad- 60 Between these 92 ment with caustic alkali at a temperature intermediate to that preferably employed when using diazo-compounds belonging to the extreme groups previously referred to.

\Ve have discovered that speaking generally the temperature required for the conversion of diazo-compounds into our new nitrosamin-compounds varies according to the acidity of the substituting groups; the conversion being the more readily effected the more strongly acid an effect these are capable of producing under the circumstances of the reaction. By this application we do not intend to claim generally the nitrosamins resulting from the treatment of the diazo-compounds herein defined with caustic alkalies but to claim the specific nitrosamin (both in the form of salt and in the free state) derived from benzidin.

The following example will serve to illustrate the manner in which our invention can best be carried into practical effect and our new nitrosamin obtained from benzidin.

Example. Production of a nitrosamt'nfrom tetrazodz'phenyL-Mix thoroughly about sixty (60) parts of benzidin with about two hundred and forty (240) parts of hydrochloric acid (containing about twenty eight per cent. (28%) of real acid H01). 0001 the mixture by external cooling to about minus five degrees centigrade (5 0.). Then add about one hundred and twenty (120) parts of powdered ice and dim;- otize by adding about fifty parts of solid sodium nitrite. Filter the tetrazo-solution so obtained and allow it to run slowly into a mixture of five hundred (500) parts of caustic soda lye containing about thirty five percent. (35%) of sodium hydrate with about one hundred and fifty (150) parts more of solid caustic'soda. Stir the solution thoroughly while runningin the tetrazo-solution and keep it cool by external cooling. The temperature must not ever exceed about ten degrees centigrade (10 0.). During the operation about one hundred and fifty (150) parts more of caustic soda are added gradually to the mixture. A pasty mixture is so obtained. In the meantime prepare a mixture of about two hundred (200) parts of solid caustic soda and about two hun dred (200) parts of caustic soda lye containing about thirty five per cent. (85%) NaOH and heat this mixture directly to about one hundred and sixty degrees centigrade (160 0.). Add the pasty mass obtained as above described gradually to this hot solution while constantly stirring. Add gradually during the operation also four hundred (400) parts of caustic soda and so regulate the temperature that it is maintained between one hundred and fifty five and one hundred and sixty degrees centigrade (155160 0.).

When no tetrazo-diphenyl can be recognized by testing with sodium naphtholate solution, allow the mixture to cool to about one hundred degrees centigrade (100 0.) and then dilute with sufficient water to render it possible to filter off the caustic liquor from the formed nitrosamin-salt. Filter hot, collect the nitrosamin'salt and dry at a temperature of about fifty degrees centigrade (50 0.).

Our new nitrosamin from benzidin possesses all the generic properties of the new class of nitrosamins hereinbefore set forth, and it occurs as a yellowish powder or paste andis further characterized by yielding a brownish violet color, when brought on the fiber with sodium beta-naphtholate and subsequently exposed to the action of the air. On treatment with excess of acid particularly in the presence of a trace of nitrous acid it is converted into tetrazo-diphenyl.

Now, What we claim is The new nitrosamin which can be derived from the tetrazo-compound of benzidin, both in the free state and as salt, which in the form of sodium salt occurs as a yellowish powder or paste soluble in water giving a slightly alkaline solution, on treatment with excess of acid particularly in the presence of a trace of nitrous acid it is converted into tetrazodiphenyl and on bringing it together with sodium beta-naphtholate on the fiber and exposing to the air, a brownish violet color is produced.

In testimony whereof we have hereunto set our hands in the presence of two subscribing witnesses.

CONRAD SOHRAUBE. CARL SCHMIDT. \Vitnesses:

ERNEST F. EHRHARDT, ADOLPH REUTLINGER. 

